By-pass clearance unloader



Feb. 8 9 REDFIELD v BY-PASS CLEARANCE UNLOADER File d Aug.4. 1926 I INVENTOIE.

Patented F eh. 8, 192 7,

' UNITED STATES PATENT orrica.

sNownsN a. n'nnrmw, or nasron, rnmzsnvama, assronon 'ro moEnsonL-mn COMPANY, or anasnv CITY, new JERSEY, a conroas'rron or new mnsnv.

BY-PASS CLEARANCE momma.

Application filed August 4, 1926. Serial No. 187.063.

I This invention relates to compressors, but more particularly to'a clearance unloader having two clearance chambers with a by- I pass or auxiliary valve between them.

5 The ob'ects of the inventionare to enable a multip icity of steps of unloadingfto be obtained by means of the two clearance chambers having the by-pa'ss connection and an inlet valve opener or'openers, sothat the In seriesof steps are obtained partly by clearance and partly by holding an inlet valve or valves open. I

The invention -is shown in one preferred form in the accompanying drawing, in which The figure isa diagrammatic representation of an unloading system partly in longitudinal sectional elevation.

Referring to the drawings, the cylinder A is provided with the piston B and the air drawn in at the inlet C is discharged at the discharge outlet D into the receiver E. The cylinder is provided with the usual inlet and discharge valves F and G and one inlet valve H is provided with a valve opener of any suitable form comprisin the fingers J connected to the stem of the piston K operat ing'in the cylinder L. A spring 0 normally retracts the fingersfand pressure fluid is suplied throu h the pipe 3 behind the piston C to held -thevalve o n.

The clearance cham e rs Q and R are preferably so arranged so that one clearance chamber is provided for each end of, the cyl inder, A by-pass valve S is located between the clearance chambers and the two chambers are provided with at least one clearance valve although in this-instance two clearance valves T and U are shown, one for each-end of the cylinder. The two clear ance valves T and U and the byass; valve S are each provided with pistons operating in cylinders W and pressure fluid is sup plied to-the pistons for opening the valves through the pipes 1, 2 and 4 respectively.

The pistons are returned by the springs first opened to produce-three quarters load.

This valve remains'open and the clearance valve U at the opposite end of the c tinder is then opened to produce half. loa The inlet valve 0 er 18 next operated to hold open the i et valve H to produce one.

quarter load while the clearance valves T and U are maintained open.

compressor.

Any suitable re ula'tor ma eludes the piston b' moved-in one direction by fluid pressure through the piper con- Finally the by-pass valve Sis open to wholly unload the be provided for carrying'out t is cycle 0 operations, it being understood that the cycle is repeated in reverse order for -reloading the compressor. The simpleregulator a shown i-n-' nected to the receiver E and retracted by the adjustable sprin l dr A'vent e is rovided for the end oft 'jdregulator 'cylin r o osite that at which pressure is introduced. The pipes 1,2,- 3 and 4 lead res tively-to the orts f, g, h and andlthe ref uced end I: i

of t e piston b gflltlltS pressure to pass successively throng the pipes 1, 2,3 and 4to operate the valves described responsively'to the pressure in the receiver.

In the o eration of the ap aratus assuming that t e compressor is duly loaded as indicated in Figure 1, when theshoulder 0 on the piston overruns the port f, the clearance valve T 'will be opened to unload the,

compressor'one quarter andflas the piston b moves to the left step by step, pressure. fluid will be successively applied through" the, ports 9, h and/g and the pipes 2, 3 and 4 respectivel to t e opposite clearance valve U then to t e valve opener ofthe inlet valve H and finally to the by-pass valve S 'for carrying out-the steps described; a

I claim: 1. In a compressor unloader, the combination-of a cylinder and piston, inlet and dis- .for controlling said clearance valve, by-pass valve and valve opener. 2. In a compressor unloader, the combination of a cylinder and piston, inlet and dis charge valves, a receiver, two clearance chambers, a by-pass valve between said chambers, at least one clearance valve for said chambers, a valve opener for one of the inlet valves, and a regulator responsive to receiver pressure for controlling said clearance valve, by-pass valve and inlet valve opener in predetermined order for step by step unloading. I

3. In a, compressor-unloader, the combination of a cylinder and piston, inlet and discharge valves, a receiver, a clearance chamher and clearance valves for each end of the cylinder, a by-pass valve between said chambers, a valve opener for one of the inemma 4. In a compressor unloader, the combiv 'nation of a cylinder and piston, inlet and dlscharge valves, a recelver, a clearance chamber and clearance valves for each end of the cylinder, at by-pass valve between said chambers, a valve opener for one of the inlet valves, and a regulator responsive to receiver pressure for controlling said clearance valves, bypass valve and inlet valve opener in predetermined order for step by step unloading. j

5., In a compressor unloader, the combination of. a cylinder and piston, inlet and discharge valves, a receiver, a clearance chamaL er and clearance valves for each end of the cylinder, a by-pass valve between said chambars, a valve opener for one. of the inlet valves, and automatic means for first opening the clearance valve at one endof the cylinder, then opening the clearance valve for the opposite end of the cylinderwhile maintaining the first clearance valve open, then opening an inlet valve by means of the said valve opener, and finally opening the by-pass valve to wholly unload the compressor.

In testimony whereof I have signed this specification. v

SNOWDEN, B. REDFIELD. 

